I doubt Fallout 4 would need an enb, considering that the only reason ENB's exist is to implement next gen post processing into the game, and I don't see why Fallout 4 wouldn't already have the majority of those technologies already. Maybe SweetFX is what would most likely come out, just to change the look of the game, but not add that many new sweet effects so to speak

_________________Writer on the Fallout Intensive Project, which aims to bring the Fallout story to the UK.Bug Tester, Interior Creator, Designer and Decorator on the Frontier Mod

as it currently stands ill be lucky to play fallout 4 at its baser settings so im not bothered by enb's but ill say its inevitable the enb creator also said he wouldn't make GTA5 enb's and i believe he has i could be wrong lol

I'm guessing yes. Even if a game looks ok at launch, there will always be people who will make em look even better. Just look at the witcher 3 for example. Fo4 will prob get sweetfx and enbs pretty fast after launch.